How stress can change your DNA

20th August 2012

Researchers in Germany say that psychological stress may increase the risk of mental and physical illness through changes to the way in which genes are expressed in an individual.

Acute psychological stress has been linked to an increased risk of all kinds of illness in previous research, but researchers at Germany's Ruhr-Universität Bochum along with colleagues at universities in Germany and the UK say they may have identified the precise way that stress causes disease.

Writing in the journal Translational Psychiatry, the researchers said they had studied gene segments involved in controlling biological stress, especially their epigenetic aspects which affect how genes are expressed in an individual and which are sensitive to environmental factors.

They found that epigenetic changes took place in the DNA of people exposed in laboratory settings to acute psychological stress of the kind triggered by a mock job interview or being asked to perform mathematical calculations under supervision.

They found that stress alters the way that genes are controlled through a process known as methylation.

The findings are important, because epigenetic changes are increasingly thought to be linked to the development of some chronic diseases, like cancer or depression.

Genetics are fixed when the fertilisation of a human egg takes place, while epigenetics describes how that fixed pattern responds to its environment and is expressed in an individual.

The epigenetic process is what controls the continued manufacture of proteins across a lifetime, once an individual's genetic hand has been dealt at conception.

Cell types are dictated by the genetic code, but the environment influences who the epigenome reads the code in determining which proteins are made by which cells.

The epigenome can be influenced by a methyl group that attaches itself to genes, and previous research has found that long-term methylation changes to DNA are associated with childhood early trauma and highly stressful life events.

For the purposes of the current study, researchers examined two genes: the one that codes for the oxytocin receptor (OXTR), which is linked to feelings of love or trust, and the one that codes for the nerve-growth factor Brain-Derived Neurotrophic Factor, or BDNF, which is linked to the development of brain cells.

The 76 study participants, all in their sixties, underwent both a mock job interview and a supervised maths test and gave blood samples before and after the tests, so that the researchers could measure the amount of DNA methylation in the two genes.

They found that the oxytocin-linked gene, which is also regarded as a powerful anti-stress hormone, showed signs of methylation, suggesting that a person would be less susceptible to its effects. There were no changes in the BDNF gene, however.